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Excess oil consumption

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DrEntropy said:
You could try it once and see. You'll never do it again. :wink:
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I've been there...Lately :crazy:

And I knew better :wall:

Had an odd problem to complicate things though.
The 23 spline clutch disk wouldn't slide on the 1st motion shaft???Until I burnished it in???
(Never thought to check [New C/R gear set and new clutch plate])
 
Yeah, little things ya take fer granted as "given"... they come back and bite ya where ya sit.


Much better to argue with it on the floor than to have things that outweigh you swingin' about on tethers, too.
 
BTW...Anyone who is thinking about putting a MGB pressure plate and clutch disk in a MGA...

You may have to remove a bit of material from the bell housing...

(As a consequence of not knowing that...I had really nice bicep tone for a couple days
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)
 
Noticed the exhaust ports in the head were very sooty. Too rich a mixture I'm thinking or perhaps too much fuel pressure. Maybe the fuel pressure is driving gas into the cylinders and diluting the oil and thus burning it. Checked the fuel pressure with the ignition on and found it to be just over 6 lbs. Too much I would surmise. Wonder what the pressure would be if the engine was on and full electric output. Got a fuel regulator today and dialed it back to just over 3 lbs Maybe I'll start there, put everything back and see what happens. Hate to remove the pistons if not necessary.
 
Should be around 4lbs.
 
Nial's RIGHT!!


No more than four/five PSI at supply. If the supply pressure is over that you have a problem.
 
I like Tony's idea about the clogged vent screen. If that crank case gets pressurized, no telling where it'll push the oil. Sure will be interesting to see what the solution to this problem is. One of those things you keep in the memory banks.

Oh well, it's to early, I need more coffee!
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Took the side vent off and it is clear. Hope the excess fuel pressure is the problem. Hope I haven't washed so much oil off the cylinder walls to cause excess ware. Compression is very good across all cylinders if that is telling or not.
 
"Smoke only when going downhill"

Now does that not suggest that it is sucking oil into the cylinders from the valve train.

I would have the head checked by another shop.
 
Go back to the basics, whay do the plugs look like, and is the smoke, black or blueish grey?

Exhuast ports will always be sooted up with catbon, the exhaust port is the toliet of the engine :smile:, thats normal, you'll also see carbon burn on the piston tops, thats normal.
 
Wouldn't it be a logical guess that, if it only happens going down hill, then I would assume the throttle is off meaning the butterfly's are closed, thus creating a high vacuum on the intake side, then wouldn't you think it's sucking oil down the intake valve stems? Doesn't take much oil to create a lot of smoke for a short period of time. Just another guess.
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PAUL161 said:
Wouldn't it be a logical guess that, if it only happens going down hill, then I would assume the throttle is off meaning the butterfly's are closed, thus creating a high vacuum on the intake side, then wouldn't you think it's sucking oil down the intake valve stems? Doesn't take much oil to create a lot of smoke for a short period of time. Just another guess.
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Good assumption, what kind of guide seals are used on it, if any, bronze or cast guides, and where they repalced by the mchaine shop when the head was rebuilt???
 
The plugs are very clean with a brownish tinge, not black and sooty. The guides were cast and installed by the machine shop and checked last week and found to be in good shape. The smoke is bluish gray, not black.
Kinda leaning toward this problem with the excessive fuel pump pressure washing oil off the exhaust valve stems and thus the black buildup on the exhaust valves and exhaust manifold. Maybe the excessive fuel is pushing past the valve stems and diluting the whole crank case oil supply.
 
ceedub said:
Kinda leaning toward this problem with the excessive fuel pump pressure washing oil off the exhaust valve stems and thus the black buildup on the exhaust valves and exhaust manifold. Maybe the excessive fuel is pushing past the valve stems and diluting the whole crank case oil supply.
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It might be running a little rich, but I would think if you had that much fuel going in to wash everything down, it wouldn't even run. If the smoke is a blue grey, you have oil getting in there somewhere. Pull the exhaust manifold and see if one port is a little wet with oil compared to the others. If one port is a little wet, then you know that's the cylinder you need to look at. I'd pull the valve springs on that cylinder and see if there is any wobble in the guide to stem. I don't know, but does the MG head use valve guide umbrellas? Also, <span style="text-decoration: underline">Are you sure the proper guides were</span> <span style="text-decoration: underline">replaced "AND" new valves installed?</span> There has to be a solution to this problem. It's sucking oil into one of those cylinders or pushing it into an exhaust port.
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ceedub said:
Kinda leaning toward this problem with the excessive fuel pump pressure washing oil off the exhaust valve stems and thus the black buildup on the exhaust valves and exhaust manifold. Maybe the excessive fuel is pushing past the valve stems and diluting the whole crank case oil supply.
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Impossible, exhaust temps are well over 1000 degrees, no fuel subjected to the exhaust stroke can not be burned up and be able to get past the guides into the head, and then the crankcase, it is impossible, study the workings of 4 stroke internal combustion engine and you'll see this. As I stated before, carbon build u in the exhaust ports and exhaust manifold/header is normal, this is where waste goes, thats the exhaust's job, if it were clean in there, it could only be for one reason, a new egine that has never been run.

Blue smoke is oil. I only put guide seals on the intake valves for the simple reason, intake sucks, and exhaust blows (thats a easy way to remember it) now it is entirely possible that oil can be sucked by a intake guides and fire in the compression stroke of the engine, thus creating blue oil smoke out the tailpipe. The other cause could be oil getting by the rings, do you know if spec ring gaps were observed, ask Basil about this one on engine he had professionally built. if the plugs are dry, then thats a good indication that the rings are sealing, then you're back to oil getting by the intakes guides as the only other possibilty, do you know if seals were used on the intakes guides, and it fo so what kind? Cast guides should have about .0015" clearnece, bronze guides twice that, but you have to have a good seal there,and the factory o-rings is far from being a good seal.
 
What a great resource this place is. I'm amazed that people from all over the continent are in my den with untold experience and the will to share it.
So, I think my problem is not with valve guides, which from what I have gleaned from many resources is not usually a problem with MG engines. Since the tops of the pistons are quite clean after 4500 miles on the engine, I'm going with rings that never seated. I'm going to remove the pan with the engine in the car, replace the rings and hone the cylinders. I might have used too much assembly oil originally and maybe that led to my problem.

Thanks to all for your help. I'll let you know how I make out.
 
And if you do take the rings out, be sure to check the ring gaps before assembly.

Have you considered using a leak-down tester? This will indentify where any problems exist before tearing it all apart.
If not familiar with them, ~Look Here~

I'm pretty sure you can buy them from Northern Tool, Harbor Freight and other internet catalog places.
 
Yep, leak down test will tell you what you want to know as far as ring, and valve seal, and pin point the problem area, been using them forever on the race cars, great tool, heck i don't een know were my compression guage is anymore :smile:
 
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